1. Field of the Invention
The present invention relates to the film transport mechanisms, and more particularly to improvements therein for transporting large image frames.
2. Description of the Prior Art
The transport of film past a projection aperture has gone through extensive technical evolution, evolution which is characteristically directed at reducing film stress in the course of intermittent transport. Typically such transport entails engagement of the film strip by mechanisms generally known under the designation "Geneva Movement" where a mechanical arm engages perforations at the edge of the film. Film transport of the foregoing form resolves the acceleration loads of the intermittent frame advancement directly at the edges of the perforations. As a consequence perforation wear and tearing is a substantial problem.
Of particular interest in the film projection art is the present interest in transporting large images. This interest is motivated by expansions in the viewed screen size, expansions which now contemplate virtually complete circular viewing.
In the past, substantial advances have been made in the film material, advances which now approach limits of polymer chemistry and thus approach limits in the best mass/strength ratio of the material. Consequently, only marginal improvements are available in optimizing film dimensions and better results are obtainable in the shaping of the film advancement transients. It is the optimization of these transient shaping techniques that is sought in the art and it is one such technique that is disclosed herein.